Tube



FIG. 1 is a perspective view of a tube showing my new design;

FIG. 2 is a front view thereof; a rearview being symmetrical to the front view;

FIG. 3 is a plan view thereof; a bottom view being identical to the plan view;

FIG. 4 is a left side view thereof; and,

FIG. 5 is a right side view thereof. 

The ornamental design for a tube, as shown and described. 